Cover for the suction box of paper



July 26, 1960 H. v. A. WARITIAINEN COVER FOR hm sucnon BOX OF PAPER MAKING MACHINES Filed July 13, 1955 FIG. 2.

FIG. 4.

//V Vf/V T017 1 flaw/4* m hvb All/F59 mar/4mm 0 FIG. 4.

COVER FOR THE SUCTION BOX OF PAPER MAKING MACHINES Henrik Viiinii Antero Wartiainen, Ohjaajantie 36D, Helsinki, Finland Filed July 13, 1955, Ser. No. 521,808

4 Claims. Cl. 162-374) The present invention relates to perforated wooden covers for suction boxes as used in the paper making machines having a conveyor element such as a Fourdrinier wire or a felt, and more particularly to a suction box cover of this type which is formed of thin elongated strips of wood veneer glued together in face to face relationship with a water insoluble adhesive and impregnated with a pine resin, the direction of the grain of the wood in all of the sheets of veneer being in the direction of the thickness of the cover, thus providing an impregnated end-of-grain working surface for engagement by the conveyor element.

As is known, conventional suction box covers are made of end-of-grain blocks of wood set across the width of the paper making machine at a slight angle with the line of travel of the conveyor element. The abutting sides of the wood blocks are provided with passages extending in the direction of grain so as to provide the requisite suction openings in the cover. To maintain a smooth unbroken surface at all times over the entire belt engaging operating area of the composite block cover it is necessary to make-these blocks of an exceptionally uniform quality of wood which will swell evenly and, generally, remain smooth notwithstanding the friction to which the suction box cover is subjected while in operation.

For this reason the blocks of wood used in assembling the conventional suction box cover are customarily made of wood having a width equal to the full block length because composite block covers are preferably not used. The suction openings are made while the wood is still wet and then ground to final shape. Ordinary plywood and many other species of wood are not suitable for this purpose and rare imported species of wood are generally used.

I have systematically experimented with suction box covers made of different kinds of materials and observed that a certain kind of wood veneer is suitable for the purpose. The novel feature of the invention is that the suction box cover consists of a plurality of single veneer sheets glued together with a water insoluble adhesive to provide a laminated end-of-grain product. The suction box cover consists of laminations of this wood veneer material assembled in the customary manner using an appropriate water insoluble adhesive. The cover is then impregnated with a resinous composition. Tests have shown that a resin derived from pine wood and marketed by the Hercules Powder Company under the trademark Vinsol may be used. This resin is preferably esterified before use as described, for example, in US. Patent No. 2,114,393, issued on April 19, 1938, to Fred H. Lane. To the esterified pine resin methyl abietate may be added for softening the impregnating medium and reducing its frictional resistance. The preferred veneer thickness is about 1 to 2 mm. and when the laminated product produced therefrom is sufficiently thick and has been shaped to the desired form it is then subjected to impregnation ice in conventional manner. tion box cover made of the described material has the following advantages over the prior art suction box covers.

The cover is homogeneous'and wear of wire or other conveyor element is reduced. The smooth surface rethe reduction in frequency of the need for regrindingthe cover is obtained, such that the cover can be used for a year without being reground. Due to the improved wearing qualities of the cover, the suction openings can be spaced more closely together than in conventional covers and the effective operating surface can thus be increased by 10% to 50%. The length of the cover is unlimited. The cover does not collect sand on its surface or crack on drying. The cover does not warp nor splinter as do conventional covers. Hence, the cover has, in practice, proved to be better than the best conventional covers.

The invention may be more clearly understood by reference to the following description together with the accompanying drawing forming a part thereof.

Referring to the drawing:

Figure 1 is a top plan view of a suction box provided with a plurality of covers in accordance with the present invention.

Figure 2 is an elevational view in transverse section of the suction box and covers shown in Fig. 1.

Figure 3 is an enlarged fragmentary top plan view of one of the covers shown in Figs. 1 and 2.

Figure 4 is a sectional view in elevation taken along the line 4-4 of Fig. 3 looking in the direction of the arrows.

Referring to Figs. 1 and 2, a suction box 10 is provided at the upper ends of its upright side walls with vertically spaced inwardly extending flanges 11 and 12. The upper flange 11 at each side of the suction box is received in a complementary groove 14 (Fig. 4) for-med in one end of each cover 13. Each cover 13 has a plurality of suction openings 15 formed therein. Each suction opening 15 extends through the cover 13 in the direction of the thickness thereof which is vertically as shown in the drawing. Each cover 13 consists of a series of thin elongated strips of wood veneer 16 held as sembled in face to face relationship by a water insoluble adhesive (not shown).

As shown in Fig. 4, the grain of the wood extends transversely of each strip 16 between the edges thereof and in the direction of the thickness of cover 13. The thin strips of wood veneer 16 thus provide an end-ofgrain working surface at the top surface of each cover 13 which is adapted for sliding engagement by the con veyor element such as the Fourdrinier wire, or felt, as the case may be, of the paper making machine. As previously described, the cover is impregnated with an esterified Vinsol pine resin to enhance Wear resistance and methyl abietate is added thereto to reduce the frictional resistance presented to the wire by the working surface.

Each cover 13 is elongated and the strips of wood veneer 16 extend longitudinally of the cover. The ends of each cover 13 are slightly oblique with respect to the longitudinal direction of the strips 16. The suction box 10 is provided with a sufiicient number of covers 13 to provide a total working surface which extends throughout the entire length of the suction box 10.

While I have shown what I believe to be the best embodiment of my invention, it will be apparent to those skilled in the art that various modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A suction box cover block for use in a paper mak- Tests have shown that a suc-- ing machine having a conveyor element, said cover block comprising a series of thin elongated strips of Wood veneer held assembled together in face to face relationship by a water insoluble adhesive to form said cover block, said cover block having a plurality of suction openings formed therein which extend therethrongh in the direction of the thickness thereof, the grain of said wood extending transversely of said strips between the edges thereof and in the direction of the thickness of said cover block to providean end-.of-grain working surface on said cover block adapted for engagement with said conveyor element, said cover block being impregnated with an esterified pine wood resin for enhancing its resistance 'to'wear.

2. A cover block according to claim 1, wherein methyl abietate is added to said ester-ified resin for reducing the frictional resistance of said working surface to said conveyor element.

3. A cover block according to claim 1, wherein said cover block is elongated and said strips extend longitudinally thereof.

4. A cover block according to claim 3, wherein methyl abietate is added to said esterified resin for reducing the frictional resistance of said working surface to said wire conveyor element.

References Cited in the file of this patent UNITED STATES PATENTS 751,095 McAnulty et a1. Feb. 2, 1904 1,822,363 Morin Sept. 8, 1931 2,042,198 Swauger May 26, 1936 1,114,393 Lane Apr. 19, 1938 2,172,445 Lutz Sept. 12, 1939 2,264,189. Richter et aL Nov. 25, 1941 2,346,785v Proulx Apr. 18, 1944 2,408,176 Proulx Sept. 24, 1946 2,412,534 Randall Dec. 10, 1946 2,503,407 Perry Apr. 11, 1950 2,503,711 Bu'llard Apr. 11, 1950 2,544,887 Leonard Mar. 13, 1951 2,581,635 Cox Jan. 8, 1952 2,611,623 Strand Sept. 23, 1952 2,618,206 Van Ryzin Nov. 8, 1952 OTHER REFERENCES 'Buttrey: Plasticizers, 1950, pages 89 to 93. Article in Modern Plastics, volume 28, No. 9., vMay 1951, pages 55 to 60. 

